Virtual Fish Put New Eyes on Underwater Toxins

by Cassandra Profita
Oregon Public Broadcasting, May 27, 2011

Scientists are using a synthetic fish fat to test for pollution in Oregon's waterways. These virtual fish are able to detect water contaminants at much lower concentrations than ever before. OPB's Ecotrope blogger Cassandra Profita reports on what these fish are finding.

On a tributary of the Hood River, scientists Jennifer Morace and Blaine Eineichner pull an unusual kind of fish out of the water.

It's a fish that's giving scientists a clearer view of water pollution in Oregon's rivers than they've ever had before.

It absorbs pollutants a lot like a fish would - accumulating them bit by bit over a long period of time. But it doesn't look anything like a fish.

Greg Fuhrer: "In reality it's really just like a paint can."

That's Greg Fuhrer of the U.S. Geological Survey.

Greg Fuhrer: "A stainless steel paint can with a bunch of holes in it. And water can flow through this cylinder, and inside of it is fish fat inside a plastic membrane."

Fuhrer has helped deploy these virtual fish in several Oregon waterways - including some that supply drinking water to Oregon cities.

These fish don't swim around. But by staying in one place for a month or longer they pick up small concentrations of chemicals scientists wouldn't otherwise be able to see.

Regular water samples measure pollution in parts per million or parts per billion. The virtual fish is measuring parts per quadrillion. Fuhrer says that's the equivalent of one drop from an eye dropper in 1,000 Olympic-sized swimming pools.

In the Hood River Valley, Warm Springs biologist Blaine Eineichner wades into Rock Springs Creek to unlatch the can of synthetic fish fat that's been in the water for two months. The tribe is using this virtual fish to test for pesticides that wash off of nearby fruit farms.

This water feeds its salmon and steelhead hatchery. Project coordinator Christopher Brun says the goal is to protect fish from chemicals that can harm their ability to reach their spawning grounds.

That can derail salmon recovery efforts.

Christopher Brun: "This is the springtime in May when there's a lot of pesticide and herbicide applications going on right now. So we're just trying to figure out how much is entering the streams or coming down the streams or even present in the streams."

The Warm Springs Tribe has been working with farmers to put plants along streams that will intercept pesticide runoff. But it's a type of water pollution that's notoriously hard to track. Brun says the virtual fish will monitor the streams year-round.

Christopher Brun: "If we're finding increased levels or new detections we're going to look in that stream for areas where pesticides may be getting into the streams and working with those landowners to reduce those inputs into the stream."

Virtual fish are giving scientists a peek at water pollutants they couldn't see before, that aren't being regulated. Things like pharmaceuticals, soap ingredients and flame retardants. They get washed down the drain, and aren't removed by water treatment plants.

Fuhrer says scientists don't know yet how much of these new pollutants are safe for fish and for people who eat fish.

Greg Fuhrer: "Some of the harder questions that we get asked oftentimes are since we measure concentrations that are at such low levels and some of the compounds are newer compounds because methodologies improved and we can now detect compounds we couldn't detect before and at lower levels it's like so what? What do we do? What does that mean?"

Environmentalists say now that we know about these emerging contaminants, we should start regulating them. But Aaron Borisenko of the Oregon Department of Environmental Quality says water regulators still see the virtual fish sampling as experimental. That’s because the levels of contaminants in the virtual fish are hard to compare with the actual concentrations in the water.

Aaron Borisenko: "I certainly think we're interested in the technology and learning more about their potential applications, but I'd say we're definitely in the cautiously optimistic phase."

Jean Godfrey represents more than 400 farmers in the Columbia Gorge Fruit Growers Association. Her group has been working with the Warm Springs Tribe to plant stream buffers and keep agricultural runoff from entering salmon-bearing streams.

She said the growers want to know what the virtual fish are finding so they can help keep the water clean and avoid regulations that would put them out of business.

Jean Godfrey "We just want to make sure that when they're testing we are aware of the results. So we know if there are any problems we can immediately get to our growers. We just want to be seen as being cooperative and doing everything we can to keep the water as clean as everybody else wants it."

In the Hood River Valley, Eineichner will wade into two streams every two months to replace the virtual fish testing for pesticides. The fat inside the canister will be sent to a lab. And a few weeks later, the Warm Springs Tribe and fruit growers will learn whether their efforts to keep chemicals out of salmon streams are working.